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Deposition of Au nanoparticles (NPs) through UV ultra-short-pulse laser ablation in vacuum is a methodology suitable for obtaining high purity supported plasmonic NPs with a superb adherence to both planar and patterned substrates. Furthermore, the peculiarity that upon sub-picosecond laser irradiation NPs form directly within the target leads to narrow and controlled size-distribution. While extensive literature theoretically models phase changes and pressure relaxation of metal targets under sub-picosecond irradiation, the evolution of the nanostructured deposit through different ablation regimes is poorly documented experimentally. In this paper, besides modeling the temporal evolution of electron and lattice temperature following sub-picosecond laser pulse irradiation of Au bulk at the threshold ablation fluence (0.1 J/cm2), we report an accurate statistical, morphological and structural characterization of the AuNP distributions as a function of the laser fluence tuned from 0.1 to 3 J/cm2 to drive the target through two ablation regimes. The occurrence of photomechanical spallation and phase explosion at low and high fluence, respectively, is correlated with the evolution of the NP deposits, which are discussed by providing a physical insight in the interplay between fluence-driven ablation regimes of the target, arrangement kinetics of the deposited species (NPs and vapour species) and (crystalline or amorphous) phase of the NPs. This knowledge is key for controlling the surface plasmon resonance response of AuNPs depending on the designed application.

Construction of low-cost and high-efficiency electrochromic electrodes with high color contrast and fast response time in electrochromic applications have led to a proliferation of studies in metal oxides. This research study presents a comprehensive overview of the electrochemical synthesis of nanoporous Cu-doped nickel oxide films on ITO-coated glass substrate and its electrochromic behavior in alkaline medium. X-ray diffraction analysis and scanning electron microscopy are used to determine the phase and morphology of the produced films. The films indicate uniform and good adhesion to the substrate. The electrochromic behavior of the deposited films is tested by means of cyclic voltammetry, chronocoulometry, repeating chronoamperometry, and electrochemical impedance spectroscopy measurements. The color change from dark brown to transparent appears reversibly well suitable under sequential potential from -0.2 to +1.0 V. After the Cu atoms incorporate into the host NiO matrix, noticeably enhancements are observed in optical modulation (57.1% at 550 nm), coloration efficiency (13.78 cm(2)/C) and response time (t(b) = 2.26 s and t(c) = 1.77 s) compared to its as-prepared NiO films. Energy level diagrams including fermi level, valance band edge and conduction band edge positions are presented based on the Mott-Schottky approximation and Tauc's method using absorbance data for the NiO and Cu:NiO films. The negative slope of the Mott-Schottky plot shows p-type conductivity for the films, and acceptor density is found as 4.44 x 10(19) cm(-3) and 5.41 x 10(19) cm(-3) for the NiO and Cu:NiO films, respectively. An equivalent electronic circuit is fitted using the measured Nyquist data of the NiO or Cu:NiO semiconductor/electrolyte system, and the calculated values of the circuit elements show significant sensitivity to the Cu doping. Therefore, our results make a major contribution to the research on energy-saving smart windows by demonstrating analyses in detail.

CdSe semiconductor thin films were grown on indium tin oxide (ITO) coated glass substrates by co-electrochemical deposition method. Deposition potential was kept at - 0.95 V vs. Ag/AgCl reference electrode for ten minutes. Deposition electrolyte includes an aqueous solution of 10 mM CdCl2, 20 mM H(2)SeO(3 )as precursors, 200 mM LiCl as complexing agent, and HCl for adjusting of pH. Deposited CdSe thin film was annealed at 500 degrees C for 30 min in air medium. Precursor and annealed CdSe thin films were characterized using a number of techniques, including SEM, EDX, XRD, UV-vis spectroscopy, and electrochemical impedance spectroscopy. SEM studies show that annealing alters the surface of precursor CdSe film from smooth to granular appearance. According to EDX analyses, the ratio of Cd/Se is close to 1.07 and 1.04 for the precursor and annealed CdSe thin film, respectively. XRD analysis shows that each film has polycrystalline structure. Precursor film has only cubic structure of CdSe, while annealed film has hexagonal structure of CdSe and cubic crystal phase of CdO. Optical energy band gap of the as-deposited CdSe film increases from 1.64 to 1.71 eV after annealing due to the mixture of the two phases. Refractive index against wavelength changes between 2.0 and 3.3. Calculations performed by using the data of Mott-Schottky measurements show that precursor CdSe film has 1.72 x 10(16 )cm(-3), while annealed film is of 3.65 x 10(17 )cm(-3 )carrier concentration. The prepared films exhibit n-type semiconductor character. The study reports energy level diagrams of the produced semiconductor CdSe thin films by using the Mott-Schottky and Tauc's approximations. The carrier transport properties in the interface between active CdSe thin film and electrolyte are discussed based on an equivalent electronic circuit simulated to the Nyquist data of the CdSe/electrolyte system.

Well-designed Z-Scheme CuS@Ag/BiVO4 photocatalyst was fabricated through a multi-step synthesis. The structure was investigated by X-Ray photolectron spectroscopy, X-Ray diffractometer, Valance-band X-Ray photoelectron spectroscopy, scanning electron microscopy, Uv-Vis DRS, and photoluminescence analysis. The activities of the samples were tested for photocatalytic oxidation of Bisphenol - A (BPA) under visible light irradiation. The photo-catalytic efficiencies of CuS@BiVO4 and CuS@Ag/BiVO4 samples were explained by conventional heterojunction and Z-scheme mechanisms, respectively. Optimum degradation of BPA as 77.1% was achieved over CuS@Ag/BiVO4 photocatalyst at the end of 3 h. In the oxidation runs performed with persulfate and hydrogen peroxide, complete degradation of BPA was achieved. The radical scavenger experiment indicated that O-2(-center dot) and h(+) play a dominated role during the photocatalysis of BPA. In the sono-photocatalysis, 850 kHz ultrasonic reactor was observed to be more effective than that of low frequency for consumption of electrical energy to degrade BPA. Reusability tests were performed with three successive runs to determine the stability of the catalyst. Toxicity result showed that the treated BPA solution was 66.3% less toxic than that of untreated BPA solution., Ege University Scientific Research Fund, The relevant study budget was provided by the Ege University Scientific Research Fund under project number of FYL-2020-22271. The authors are grateful for the financial support provided by the Ege University Scientific Research Fund. We would like to express our gratitude to Prof. Dr. G_onul Gunduz for guiding us through this study.

Herein, pure and cobalt (Co) doped cadmium oxide (CdO) thin films successfully deposited onto glass slides by successive ionic layer adsorption and reaction (SILAR) method. And, the structural, morphological, optical, and electrical properties were studied by employing X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), Energy dispersive X-ray analysis (EDAX), Ultraviolet-visible spectroscopy (Uv-vis), Photoluminescence (PL) spectrum, I-V measurements for the produced samples. The XRD analysis uncovered that the CdO films exhibited cubic phase of cadmium oxide with the preferred orientation (111) plane. And, it showed that Co atoms successfully incorporated into the CdO lattices as no secondary phases were detected in the XRD spectra. The FE-SEM images displayed that the introduced impurities modified the surface morphologies. The EDAX analysis definitely proved the presence of the aimed materials (Cd, O, and Co) on the SILAR grown samples. The Uv-vis spectroscopy showed that optical energy bandgap enhanced from 2.5 eV to 2.93 eV as CdO nanostructures (NSs) doped with the different Co doping concentrations. The PL spectrum revealed that the luminescence characteristics of produced films were evidently influenced by the Co doping in the CdO NSs. Also, the resistivity of the produced samples was found to be decreased by the help of the I-V measurements.

In this study, the effects of Cu and Fe additives on the structural, dielectric, magnetic, thermal and morphology of hydroxyapatite (HAp) samples were investigated and reported in detail for the first time. The prepared systems were also modeled and examined theoretically. It can be said that both additives affect the thermal behavior of the HAp structure. The addition of Cu affected the morphology of submicron-sized particles with spherical-like shapes with a low degree of agglomeration. Diffuse reflection data revealed that the energy band gap values decreased as Cu was added to the Fe-based HAp structure. The dielectric constant (epsilon') had high values at low frequencies in all samples and decreased with increasing frequency. It could be concluded that Fe/Cu incorporation to hydroxyapatites enhanced its thermal, magnetic, and dielectric properties required for mimicking natural HAps to open a successful venue for medical application in the healing regeneration of bone. Deanship for Scientific Research of Imam Abdulrahman Bin Faisal University [2020-170-IRMC] The authors acknowledge the financial supports provided by the Deanship for Scientific Research of Imam Abdulrahman Bin Faisal University (Project application No. 2020-170-IRMC) . Also, the authors acknowledge the facilities used at Institute for Research and Medical consultations (IRMC) at Imam Abdulrahman Bin Faisal University. WOS:000715133400001 2-s2.0-85118341098

Summary: The partitioning of solar radiation in the Arctic sea ice during the melt season is investigated using a radiative transfer model containing three layers of melt pond, underlying sea ice, and ocean beneath ice. The wavelength distribution of the spectral solar irradiance clearly narrowed with increasing depth into ice, from 350–900 nm at the pond surface to 400–600 nm in the ocean beneath. In contrast, the net spectral irradiance is quite uniform. The absorbed solar energy is sensitive to both pond depth (Hp) and the underlying ice thickness (Hi). The solar energy absorbed by the melt pond (Ψp) is proportional only to Hp. However, the solar energy absorbed by the underlying ice (Ψi) is more complicated due to the counteracting effects arising from the pond and ice to the energy absorption. In September, Ψp decreased by 10% from its August value, which is attributed to more components in the shortwave band (

Zinc oxide (ZnO) thin films were deposited using RF sputtering followed by plasma immersion ion implantation for 10–70 s to dope phosphorus on ZnO. Optical and structural characteristics from particular experiments (Photoluminescence (PL)), High resolution X-ray diffraction (HRXRD) and energy dispersive x-ray spectroscopy (EDX) confirms presence of phosphorus doping in implanted ZnO thin films. Dominant peak at around 3.35 eV measured from low temperature PL (18 K) measurement which assign as neutral acceptor-bound exciton peak. Two peaks: free electron acceptor and donor bound acceptor were observed at around 3.32 and 3.25 eV. The acceptor level was observed at 107 meV above the valence band. All samples exhibited dominant (002) crystal orientation peak in HRXRD measurements, indicating perfect c-axis orientation. Highest carrier (hole) concentration of 9.94 × 1017 cm−3 was measured from 60 s implanted sample. Formation of complex acceptor PZn-2VZn was justified by EDX measurements.

Plant functional traits (PFTs) underpin ecosystem processes and therefore ecosystem service provision. If PFTs are possible to detect and discriminate spectrally, then it may be possible to use remote sensing applications to map ecosystem processes or services within and across landscapes. As a first step towards this application, we explored whether functional groups of 22 dominant South African wetland species were spectrally separable based on their PFTs. We measured 23 biochemical and morphological PFTs in combination with spectra from 350 to 2349 nm using a handheld radiometer. First, we evaluated the possibility of accurately predicting morphological and biochemical PFTs from reflectance spectra using three approaches: spectrum averaging, redundancy analysis (RDA), and partial least squares regression (PLSR). Second, we established whether functional groups and species were spectrally distinguishable. We found seven PFTs to be important in at least two of the three approaches: four morphological and three biochemicals. Morphological traits that were important were leaf area (PLSR: r² = 0.40, regression: r² = 0.41), specific leaf area (r² = 0.67), leaf mass (r² = 0.43, r² = 0.38), and leaf length/width ratio (r² = 0.62). Biochemical traits that play a role in the structural composition of vegetation, like lignin content (r² = 0.98, r² = 0.54), concentration (r² = 0.45) and cellulose content (r² = 0.57, r² = 0.49), were found to be important by at least two of the analyses. Three other traits were important in at least one of the analyses: total biomass (r² = 0.56), leaf C/N ratio (r² = 0.99), and cellulose concentration (r² = 0.76). Redundancy analysis suggests that there is a large percentage (52%) of the spectrum not explained by the PFTs measured in this study. However, spectral discrimination of functional groups, and even species, appears promising, mostly in the ultraviolet A part of the spectrum. This has interesting applications for mapping PFTs using remote sensing techniques, and therefore for estimating related ecosystem processes and services. ispartof: REMOTE SENSING OF ENVIRONMENT vol:210 pages:25-34 status: published

Multifunctional plasmonic based hybrid noble metal nanostructures are of great importance for the various technological applications as it is an important fundamental building block of optoelectronics, photovoltaic and photonics devices. The nanoscale behavior of Cu nanoparticles diffused into a glass matrix through the simple ion exchange method combined with thermal treatment at various temperatures have been investigated. The effects of thermal treatment on the plasmonic response, structural, morphological and optical studies of Cu nanoparticles embedded in the glass matrix have been studied using UV-visible absorption spectroscopy, X-ray Diffraction, Field Emission Gun Transmission Electron Microscope and photoluminescence spectroscopy. Scanning electron and Transmission electron micrographs confirmed the presence of spherical shaped Cu nanoparticles and embedded within the glass matrix after thermal treatment at various temperatures. Enthalpy (Delta H), entropy (Delta S) and Gibbs energy (Delta G) empirical parameters interpreted for the temperature driven growth mechanism of Cu nanoparticles. Thermodynamic empirical parameters Delta H, Delta S and Delta G were obtained with activation energy (9.81 kJ/mol) which was calculated using the Arrhenius linear equation. Cu nanoparticles in the glass matrix are suitable and promising material for blue-green emission of the Cu+ ions with a possible application in laser technology. (C) 2018 Elsevier B.V. All rights reserved.

Constraints of the single layer quantum dot (QD) led to the investigation of alternative heterostructures for the next generation high performance optoelectronic devices. In this work, the periodicity of straincoupled QD layers were optimized via growing Bilayer, Trilayer, Pentalayer, and Heptalayer structures with a novel perspective. Both theoretical and experimental investigations were done to acquire a better understanding of the dot periodicity. Proposed QD structures exhibited redshift in the PL peaks compared to the uncoupled one. Monomodal dot size distribution and narrow full width half maximum (FWHM) were observed for Bilayer, and Trilayer quantum dot infrared photodetectors (QDIPs). However, an increase in the FWHM in the Pentalayer QDIP, and a multimodal dot size distribution in the Heptalayer QDIP were witnessed. The highest activation energy (303.42 meV) claimed by the Trilayer sample substantiated better vertical confinement of carriers. There was a 24.4% enhancement in the activation energy, and 3.7% reduction in the FWHM value of PL peak for the Trilayer sample, compared to the uncoupled QDIP. For accentuating the advantages of Trilayer QDIP, measurements of photoluminescence excitation (PLE), IV characteristics and spectral response were carried out and compared with others. The Trilayer device with optimized periodicity of QD layers offered the lowest dark current density (3.7 x 10(-6) A/cm(2) at -1 V, 77 K), high temperature operability (90 K), and peak responsivity of 461 mA/W (at -2 V, 90 K). (C) 2017 Elsevier B.V. All rights

Dilute nitride InGaAsSbN layers grown by low-temperature liquid phase epitaxy are studied in comparison with quaternary InGaAsN layers grown at the same growth conditions to understand the effect of Sb in the alloy. The lattice mismatch to the GaAs substrate is found to be slightly larger for the InGaAsSbN layers, which is explained by the large atomic radius of Sb. A reduction of the band gap energy with respect to InGaAsN is demonstrated by means of photoluminescence (PL), surface photovoltage (SPV) spectroscopy and tight-binding calculations. The band-gap energies determined from PL and ellipsometry measurements are in good agreement, while the SPV spectroscopy and the tight-binding calculations provide lower values. Possible reasons for these discrepancies are discussed. The PL spectra reveal localized electronic states in the band gap near the conduction band edge, which is confirmed by SPV spectroscopy. The analysis of the power dependence of the integrated PL has allowed determining the dominant radiative recombination mechanisms in the layers. The values of the refraction index in a wide spectral region are found to be higher for the Sb containing layers.

Si doped AlN films were grown on GaN/Sapphire templates by plasma assisted molecular beam epitaxy (PAMBE) technique. We show that employing an excimer laser annealing with optimized power and frequency rather than the conventional thermal annealing could be a potential alternative route towards improving the structural and electrical properties of AlN layers. Upon optimized laser annealing of the Si-doped AlN layer, the electron concentration was achieved to be as high as similar to 4.9 x 10(18) cm(-3) which was measured by Raman spectroscopy measurement and was further cross checked by standard Hall measurement which estimated the same as similar to 7.4 x 10(18) cm(-3) with a mobility of 109 cm(2)/V-sec. The improvement of free carrier concentration was leveraged by improvement of structural properties. The r.m.s surface roughness of the Si-doped AlN layers measured by atomic force microscopy was reduced to 0.76 rim and corresponding residual stress estimated by high resolution XRD and Raman measurement was found to be less than half compared to the in-situ Si-doped sample. Thus laser annealing is proposed to be a suitable method to achieve high electron concentration in Si doped AlN films without compromising the structural quality.

Magnesium oxide (MgO) thin films were grown by successive ionic layer adsorption reaction (SILAR). As a result of Fe doping, modifications of the morphological, structural and optical properties of MgO thin films were reported. UV-Vis spectroscopy, photoluminescence (PL), X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were performed to investigate the consequences of Fe doping. The energy band gap for the undoped MgO and Fe doped MgO thin films were obtained to be between 3.57 and 4.00 eV. The density of PL spectrum peaks were observed to decrease with the addition of Fe which shifted to the UV region of the spectrum. The XRD measurement of MgO thin films were of nanostructures which possess a cubic structure with order of planes (200) and (220). The SEM measurements of the thin films were of nano structure. All in all, pure MgO and Fe doped MgO nanostructures were successfully produced in the light of variable characterization techniques., Agri Ibrahim Cecen University [PMYO.20.001], The authors thank Agri Ibrahim Cecen University for financial sup-port of the study (Project no: PMYO.20.001) .

In the present study, pure and Mn doped SnO2 thin films were grown by performing successive ionic layer adsorption and reaction (SILAR) method on the glass substrates at room temperature. The fabricated thin films have been studied to assess the influence of Mn doping on structural, morphological, and optical properties of SnO2 crystal lattice. The X-ray diffraction (XRD), Ultraviolet-visible spectrometer (UV-Vis), Energy dispersive X-ray analysis (EDAX), Scanning electron microscope (SEM), Raman, X-ray photoelectron spectroscopy (XPS), and Photoluminescence (PL) spectra measurements were conducted. After the XRD and SEM evaluations, it was found that the grown nanoparticles were in rutile type tetragonal structure of polycrystalline nature which was supported by Raman results. And, the surface morphologies were also observed to be affected from the varied concentrations of Mn doping. Besides, the EDAX evaluation confirmed the integration of Mn content next to Sn and O ions in the synthesized SnO2 nanostructures by SILAR method. The UVi-vis analysis disclosed that the absorbance of the prepared thin films had a clear inclination to increase as doping concentration intensified. In addition to that, the optical investigations also uncovered the bandgap of SnO2 nanocrystallines could be tuned from 2.61 eV to 2.00 eV by exposing them to the different levels of Mn ions. Furthermore, the Photoluminescence spectra evidently acknowledged the possibility of engineering optical characteristics by showing increased luminescent emission intensity values right after the introduction of impurities into the SnO2 lattice. The XPS results further verified the manganese and tin valences existed in the produced thin films., Agri Ibrahim Cecen University [MYO-21-003], The authors thank Agri Ibrahim Cecen University for financial support of the study (Project no: MYO-21-003).

The bio-essential trace metal iron (Fe) has poor inorganic solubility in seawater, and therefore dissolution is dependent on organic complexation. The Arctic Ocean is subject to strong terrestrial influences which contribute to organic solubility of Fe, particularly in the surface. These influences are subject to rapid changes in the catchments of the main contributing rivers. Here we report concentrations and binding strengths of Fe-binding organic ligands in relation to spectral properties of Dissolved Organic Matter (DOM) and concentrations of humic substances. Full-depth profiles of Fe and Fe-binding organic ligands were measured for 11 stations, good agreement to previous studies was found with ligand concentrations between 0.9 and 2.2 equivalent nM of Fe (Eq. nM Fe) at depths > 200 m. We found nutrient-like profiles of Fe in the Atlantic-influenced Nansen basin, surface enrichment in the surface over the Amundsen and Makarov basins and scavenging effects in the deep Makarov basin. A highly detailed surface transect consisting of two sections crossing the surface flow from the Siberian continental shelf to the Fram Strait, the TransPolar Drift (TPD), clearly indicates the flow path of the riverine contribution to Fe and Fe-binding organic ligands with concentrations of 0.7 to 4.4 nM and 1.6 to 4.1 Eq. nM Fe, respectively. This is on average 4.5 times higher in DFe and 1.7 times higher in Fe-binding organic ligands than outside the TPD flow path. Conditional binding strengths of ligands in the entire dataset were remarkably similar at 11.45 ≤ LogK′ ≤ 12.63. Increased organic Fe-binding organic ligand concentrations were evident in the Arctic Ocean surface. To better identify the organic substances responsible for Fe complexation in the Arctic Ocean, diverse analytical approaches and a standard other than Suwannee River Fulvic Acid are recommended.

ZnS/p-Si heterojunction diode has been successfully fabricated by depositing the ZnS thin films on p-type Si substrates using thermionic vacuum arc technique (TVA). The structural analysis was performed with X-ray diffraction (XRD) and Atomic force microscopy (AFM). The results revealed that ZnS thin film demonstrates nano-crystalline behavior with very smooth and homogeneous surface properties. The type was determined as n-type and the carrier concentration was found approximately 3.1 +/- 10(17) cm(-3) of the ZnS thin film by means of Hall Effect measurement. The dark current-voltage (I-V) and the capacitance- voltage (C-V) measurements with different frequencies were performed to determine the characteristics of the ZnS/p-Si heterojunction diode at room temperature. I-V results show that the diode has a good rectifying characteristic with excellent rectification ratio. The electrical parameters of the diode have been obtained by using current transport mechanism. It was found that the barrier height calculated from dark I-V measurements is in good agreement with the value obtained from C-V measurements at a frequency of 1.5 MHz. The series resistance and the built in potential of the fabricated diode were calculated as 3.6 k Omega and 0.7 V using Cheung and Cheung's equation and C-V measurement, respectively. The low cost and effective film production method were utilized to fabrication of heterojunction diode and to investigate characteristics.

This study investigates the vertical inter-QDs spacing (VIDS) in a coupled bilayer quantum dots (CBQD) heterostructure using cross-sectional High Resolution Transmission Electron Microscopy (HRTEM). Simultaneously, we also examined the interrelationship of VIDS with the strain energy inside the CBQD stack. As a continuation, the CBQD heterostructure were further explored from different aspects of growth parameters, such as the deposition of ultrathin GaAs spacer layer of 4.0-4.5 nm between the seed and active layer of QDs, the effect of larger monolayer coverage (3.2 ML) of seed layer QDs, and the optimization of growth rates for the CBQDs. Moreover, we present a model technique to characterize the in-plane 2 theta chi/Phi of InAs QDs and GaAs at (002) and (004) planes in order to analyze the strain. This study was the first of its kind to look at the formation of self-assembled In-(x) Ga(1-x) As layer at the interface across the ultrathin GaAs spacer and InAs QDs, verified with HRTEM images. Smaller size of QDs formed in the seed layer led to the formation of a non-uniform self-assembled In-(x) Ga(1-x) As layer. The problem of non-uniformity of In-(x) Ga(1-x) As layer was resolved by increasing the seed layer monolayer coverage from 2.5 to 3.2 ML. The percentage of gallium adatoms inter-diffused into the outer surface of InAs QDs to form the self-assembled In-(x) Ga(1-x) As layer was similar to 31% for VIDS similar to 1.4 +/- 2 nm. (C) 2017 Elsevier B.V. All rights reserved.

The past two years have witnessed heightened interest in metal-halide perovskites as promising optoelectronic materials for solid-state light emitting applications beyond photovoltaics. Metal-halide perovskites are low-cost solution-processable materials with excellent intrinsic properties such as broad tunability of bandgap, defect tolerance, high photoluminescence quantum efficiency and high emission color purity (narrow full-width at half maximum). In this review, the photophysical properties of hybrid perovskites, which relates with light-emission, such as broad tunability, nature of the recombination processes and quantum efficiency are examined. The prospects of hybrid perovskite light-emitting diodes and lasers, and their key challenges are also discussed.

The Ca0.85-1.5xGdxEu0.1+0.05 square 0.5xWO4(0

DC reactive magnetron sputtering of zinc target in argon-oxygen sputtering atmosphere has been used to grow ZnO thin films/nanorods on Si in a wide substrate temperature range of 300-750 degrees C and under different sputtering conditions, namely, DC power, sputtering pressure and oxygen percentage in the sputtering atmosphere. Powder X-ray diffraction, Raman spectroscopy and a combination of top-down and cross-sectional scanning electron microscopy studies of ZnO films and nanorods grown under different conditions, have shown that substrate temperature critically controls their growth behavior and morphology, eventually resulting in the growth of vertically c-axis oriented, highly aligned and separated ZnO nanorods at substrate temperatures of 700-750 degrees C. The strongly substrate temperature dependent growth of nanorods is explained by considering that the growth above 600 degrees C, takes place in the 'desorption regime', in which, the surface diffusion length decreases exponentially with temperature. The diameter of nanorods increases with increase of DC power or decrease of sputtering pressure, which is attributed to the increase of surface diffusion length at higher deposition flux. The morphology of ZnO nanorods is not significantly affected by oxygen percentage in the sputtering atmosphere, since it does not influence the deposition flux. (C) 2016 Elsevier B.V. All rights reserved.

The effect of the capping layer and the number of strain-coupled stacks on the optoelectrical properties of In0.5Ga0.5As quantum dot infrared photodetectors (QDIPs) are reported in this paper. GaAs-capped and InGaAs-capped bilayer, trilayer, pentalayer, and heptalayer QDIPs were grown for the first time and analyzed. The ground-state photoluminescence emission of all coupled QDIPs redshifted relative to that of the uncoupled QDIPs. All coupled InGaAs-capped QDIPs exhibited monomodal spectral response, whereas among GaAs-capped QDIPs, only the bilayer QDIP exhibited monomodal response. The optimal activation energy (339.87 meV) and full width at half maximum (FWHM; 16 meV) as well as the lowest dark current density (6.5E−8 A/cm2) at 100 K, and −1 V bias were observed for the InGaAs-capped trilayer QDIP among all due to better dot confinement, homogeneity, and also better strain coupling between the vertically stacks QD layers. The peak spectral response at 7.08 µm obtained from this QDIP had an ultranarrow FWHM of 8.67 meV, making it useful for hyperspectral applications in the infrared region.

International audience; In this study the correlation between bulk chemistry and optical properties for a set of Eu-bearing phosphate glasses, containing different alkali elements, synthetized in air and under NH3 flux, was investigated. The chemistry of the glass strongly influences several properties and the effects of bulk chemistry and synthesis conditions on glass structure and on thermal and optical properties are discussed. In alkali-phosphate glasses studied by absorption and photoluminescence spectroscopy we verified that Eu2+ emission band shifts toward higher wavelengths by substituting the alkali cation (Na

InN thin films are grown on GaN/sapphire substrates with varying the nitrogen plasma power in plasma assisted molecular beam epitaxy (PA-MBE) system. In order to evaluate the effect of nitrogen plasma power on the different properties of the InN films, several characterization viz, x-ray diffraction, atomic force microscopy, photoluminescence measurement, infra-red spectroscopy and Hall measurement were performed. Two interesting phenomena observed from the measurements are described in this paper. Firstly, it is found from both the photoluminescence and infrared spectroscopy that only by varying the nitrogen plasma power (thus the BIN ratio), one can fine tune the optical absorption edge, i.e., the effective band gap of InN from similar to 0.72 eV to similar to 0.77 eV. Secondly, it is inferred that the film grown with stoichiometric condition (III/V similar to 1) exhibits the best structural and electrical properties. (C) 2016 Elsevier Ltd. All rights reserved.

We studied the loadings of dissolved organic matter (DOM) and nutrients from the Neva River into the Eastern Gulf of Finland, as well as their distribution within the salinity gradient. Concentrations of dissolved organic carbon (DOC) ranged from 390 to 840 mu M, and were related to absorption of colored DOM (CDOM) at 350 nm, a(CDOM)(350), ranging from 2.70 to 17.8 m(-1). With increasing salinity both DOC and a(CDOM) decreased, whereas the slope of a(CDOM) spectra, S-CDOM(300-700), ranging from 14.3 to 21.2 mu m(-1), increased with salinity. Deviations of these properties from conservative mixing models were occasionally observed within the salinity range of approximately 1-4, corresponding to the region between 27 and 29 degrees E. These patterns are suggested to mostly reflect seasonal changes in properties of river end-member and hydrodynamics of the estuary, rather than non-conservative processes. On the other hand, observed nonlinear relationships observed between a(CDOM)*(350) and S-CDOM(275-295) emphasized the importance of photochemistry among various transformation processes of DOM. Dissolved inorganic nitrogen was effectively transformed in the estuary into particulate organic nitrogen (PON) and dissolved organic nitrogen (DON), of which DON was mostly exported from the estuary, enhancing productivity in nitrogen limited parts of the Gulf of Finland. DON concentrations ranged from 12.4 to 23.5 mu M and its estuarine dynamics were clearly uncoupled from DOC. In contrast to DOC, estuarine DON dynamics suggest that its production exceeds losses in the estuary. Total nitrogen (TN) and phosphorus (TP) loadings from the Neva River and St. Petersburg were estimated as 73.5 Gg N yr(-1) and 4.2 Gg P yr(-1), respectively. Approximately 59% of TN and 53% of TP loads were in organic forms. DOC and DON loadings were estimated as 741.4 Gg C yr(-1) and 19.0 Gg N yr(-1), respectively. Our estimate for DOC loading was evaluated against a previously published carbon budget of the Baltic Sea. According to the updated model, the Baltic Sea could be identified as a weak source of carbon into the atmosphere. (C) 2016 The Authors. Published by Elsevier B.V.

In the present work structural, electrical, magnetic and magnetodielectric properties of BaTi1-xFexO3 (0%

The present study is concerned with the development and application of Lattice Boltzmann method based numerical scheme for investigating the thermal response of laser irradiated biological tissue phantom during laser-based photo-thermal therapy. The Lattice Boltzmann Method (LBM) has been employed for analyzing the transport of short-pulse radiation within the body of the tissue phantom that has been considered as the participating medium. In order to determine the two-dimensional temperature distribution inside the tissue medium, the transient form of radiative transfer equation (RTE) has been coupled with the energy equation modeled based on dual phase lag (DPL) heat conduction framework. The LBM-based solution of the coupled RTE and DPL-based numerical model has been benchmarked against the results available in the literature. Results have been presented in the form of two-dimensional temperature distributions, spatial and temporal profiles of temperatures within the body of the laser-irradiated biological tissue phantoms. Effects of phase lags associated with the heat flux (TO and temperature gradients (TT) on the resultant temperature distributions inside the laser irradiated tissue phantom have also been analyzed and discussed. Thereafter, the temperature distribution inside the biological tissue phantom embedded with optical inhomogeneities has been determined using the DPL-based model. Results of the study clearly reveal the successful implementation of LBM-based numerical approach in analyzing the thermal response of laser-irradiated biological tissue phantoms. The inherent properties associated with non-Fourier heat conduction models have also been explicitly brought out in the context of photo-thermal therapy. (C) 2015 Elsevier Masson SAS. All rights reserved.

The chemical and light-absorption dynamics of organic aerosols (OAs), a master variable in the atmosphere, have yet to be resolved. This study uses a comprehensive multidimensional analysis approach for exploiting simultaneously the compositional changes over a molecular size continuum and associated light-absorption (ultraviolet absorbance and fluorescence) properties of two chemically distinct pools of urban OAs chromophores. Up to 45% of aerosol organic carbon (OC) is soluble in water and consists of a complex mixture of fluorescent and UV-absorbing constituents, with diverse relative abundances, hydrophobic, and molecular weight (Mw) characteristics between warm and cold periods. In contrast, the refractory alkaline-soluble OC pool (up to 18%) is represented along a similar Mw and light-absorption continuum throughout the different seasons. Results suggest that these alkaline-soluble chromophores may actually originate from primary OAs sources in the urban site. This work shows that the comprehensive multidimensional analysis method is a powerful and complementary tool for the characterization of OAs fractions. The great diversity in the chemical composition and optical properties of OAs chromophores, including both water-soluble and alkaline-soluble OC, may be an important contribution to explain the contrasting photo-reactivity and atmospheric behavior of OAs. (C) 2015 Elsevier Ltd. All rights reserved.

It has been recognized that the commonly used discrete dipole approximation (DDA) for calculating the optical properties of plasmonic materials may exhibit slow convergence for a certain region of the complex refractive index. In this work we investigate the quantitative accuracy of DDA for particles of different shapes, with silver as the plasmonic material. As expected, the accuracy and convergence of the method as a function of the number of dipoles is relatively good for solid spheres and rounded cubes whose size is of the same order as the wavelength of the localized surface plasmon resonance in silver. However, we find that for solid particles much smaller than the resonance wavelength, and for silver-silica core-shell particles in particular, DDA does not converge to the correct limit even for 10(6) dipoles. We also find that the slow convergence tends to be accompanied by strong, discretization dependent oscillations in the particle's internal electric field. We demonstrate that the main factor behind the slow convergence of the DDA is due to inaccuracies in the plasmonic resonances of the dipoles at the surface of the particles. (C) 2015 Elsevier Ltd. All rights reserved.

Cryogels are an outstanding class of materials with special and functionalized physical properties in various fields and privileges for different industrial applications. Due to unique properties of quantum dots, properties of cryogels can be engineered by adding quantum dots in. In this study, both p(HEMA)-based cryogel and CdSe QDs synthesized and characterized, separately. Then, CdSe QDs were loaded into p(HEMA) cryogels by immersing cryogel into QDs solutions. FTIR-ATR, SEM and TGA characterizations were performed to ensure that CdSe QDs penetrate p(HEMA) cryogels effectively. Dielectric properties of CdSe QDs-loaded cryogel were investigated using Electrical Impedance Spectroscopy (EIS). Real and imaginary parts of dielectric constants were decreased significantly at low frequencies in QD-loaded cryogels. While real part of impedance was increased in CdSe QDs-loaded cryogel at low frequencies. In addition, at high frequencies, those parameters were observed to be same in both cases. Duzce University Scientific Research Project (DUBAP)Duzce University [2017.06.03.592] Authors kindly would like to thank Duzce University Scientific Research Project (DUBAP) Coordination for the support with the project number of 2017.06.03.592. WOS:000562679400007 2-s2.0-85087508329

Infrared microscopy is used to obtain through-thickness oil temperature measurements from EHL contacts between different surface materials (steel, silicon nitride and zirconia) for the lubricants Santotrac 50 and PAO4. The measurement technique was first adapted to overcome focussing issues due to the partially transparent zirconia surface. Results were used to infer in-contact rheological behaviour of the lubricants. Santotrac 50 shows significant shear localisation under all conditions with the position of the shear heating zone being highly affected by the contact surfaces' thermal properties. For PAO4, the shear profile depends on the contact surfaces’ thermal properties with moderate to high surface conductivities favouring uniform shearing, whereas highly insulating surfaces (zirconia) cause shear localisation at the surface for both lubricants. These results are used to interpret friction measurements and show how the thermal properties of surfaces can be used to control rheology and friction. This paper is prefaced by a review of thermal EHL theory upon which our analysis is based.

In this work, ZnO particles were fabricated by sol-gel method at different heating rate at 500 degrees C for 2 h. The ZnO powders were analysed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and photoluminescence, respectively. The effect of heating rate on photocatalytic activities of ZnO particles was evaluated by degradation of methylene blue (MB). The non-isothermal kinetics and thermodynamic properties were also estimated. The XRD results showed that ZnO had hexagonal wurtzite structure. The different heating rate didn't influence the surface morphology of ZnO powders. It was observed that the heating rate had a profound effect on reduction of band gap and photocatalytic performances. The band gap of the ZnO particles varied from 3.10 to 3.17. The ZnO sample prepared at 1 degrees C/min exhibited the highest photocatalytic activity. Its relative photocatalytic degradation rate and kinetic constant were 92.7% and 1.069x10(-2) min(-1), respectively. The results might be ascribed to low bulk vacancies, high surface oxygen vacancies and narrow band gap energy. Also, ZnO photocatalysts showed good stability after four sequence tests. This study provides a new strategy to improve the photocatalytic performances of ZnO photocatalyst for the degradation of organic contaminant.

Carbon films and coatings are industrially very versatile and have a multiplicity of applications, such as conductive coatings or chemical and thermal protection layers. However, in most cases they are fabricated by the expensive vapor process, which has prevented a wider commercialization of these products. Herein, carbon films are fabricated using an inexpensive polymer-solution-based or sol–gel coating process, exemplified by spin coating of thin layers. As carbon precursor, the oligomeric form of acrodam, a high nitrogen-containing and non-volatile compound which is known to have excellent carbon yields, was employed. The oligomer is synthesized from commercially available starting materials (diaminomaleonitrile (DAMN) and acrolein) and dissolves in various organic solvents. The carbonized films were found to be homogeneous, optically flat, void- and crack-free, and were fabricated with up to 800 nm thickness after a carbonization step. High conductivities (up to 334 S cm −1 ) were achieved at the carbonization temperature of 1000 °C.

Zinc oxide (ZnO) nanostructures find applications in optoelectronic devices, photo voltaic displays and sensors. In this work zinc oxide nanostructures in different forms like nanorods, tripods and tetrapods have been synthesized by thermal evaporation of zinc metal and subsequent deposition on a glass substrate by vapor transport in the presence of oxygen. It is a comparatively simpler and environment friendly technique for the preparation of thin films. The structure, morphology and optical properties of the synthesized nanostructured thin film were characterized in detail by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and photoluminescence (PL). The film exhibited bluish white emission with Commission International dEclairage (CIE) coordinates x = 0.22, y = 0.31. (C) 2015 Elsevier Ltd. All rights reserved.

Bionanocomposite coatings with antimicrobial activity comprising polyvinyl alcohol (PVA)-capped silver nanoparticles embedded in chitosan (CS) matrix were developed by a green soft chemistry synthesis route. Colloidal sols of PVA-capped silver nanoparticles (AgNPs) were synthesized by microwave irradiating an aqueous solution comprising silver nitrate and PVA. The bionanocomposites were prepared by adding an aqueous solution of chitosan to the synthesized PVA-capped AgNPs sols in appropriate ratios. Uniform bionanocomposite coatings with different contents of PVA-capped AgNPs were deposited onto titanium substrates by \"spread casting\" followed by solvent evaporation. Nanoindentation and antimicrobial activity tests performed on CS and bionanocomposites revealed that the incorporation of PVA-capped AgNPs enhanced the overall functional properties of the coatings, namely their mechanical stability and bactericidal activity against Escherichia coli and Staphylococcus aureus. The coated specimens maintained their antimicrobial activity for 8 h due to the slow sustained release of silver ions. The overall benefits for the relevant functional properties of the coatings were shown increase with increasing contents of PVA-capped AgNPs in the bionanocomposites. (C) 2015 Elsevier Ltd. All rights reserved.

Optical properties of metallo-dielectric (Gold@silica) composites were measured using different characterizing techniques viz. UV-Visible and photoluminescence (PL) spectroscopy. Reflection spectra showed the Bragg reflection peak shifted to longer wavelength and was broadened with the shell growth. The PL spectra showed the presence of visible and infrared bands. While the visible emission is explained by radiative recombination caused by interband transitions, the infrared emission is accounted for by the intraband transitions. Raman spectroscopy of methyl red (MR) indicator dye adsorbed on metallo-dielectric films has shown an enhancement in the Raman signals on incomplete shells. The enhancement is ascribed to the surface roughness and nanogaps making the synthesized metallo-dielectric particles a potential substrate for surface enhanced Raman spectroscopy (SERS). (c) 2014 Elsevier B.V. All rights reserved.

We demonstrate a ten-fold increase in photoluminescence (PL) efficiency from 50 keV H- ion-implanted InAs/GaAs quantum dots (QDs) at a temperature of 8 K and/or 145 K. Enhancement occurred without post-annealing treatment. PL efficiency increased with increasing implantation fluence from 6 x 10(12) ions/cm(2) up to an optimum value of 2.4 x 10(13) ions/cm(2), beyond which PL efficiency decreased drastically (up to a fluence of 2.4 x 10(15) ions/cm(2)). Passivation of non-radiative recombination centres (due to direct interaction of H- ions with lattice defects) and de-excitation of photo-generated carriers to QDs through quantum mechanical tunnelling via H- ion-induced defects (e-traps) that are created near the QD-cap layer interface, resulted in PL efficiency enhancement. Shallow e-traps with activation energy similar to 90 meV and 30 meV created near the conduction band of GaAs cap layer for the samples implanted with H- of fluence 6 x 10(12) and 2.4 x 10(13) ions/cm(2) respectively are identified using low temperature PL study. Contribution of de-trapped electrons from the e-traps to the QDs enhanced the PL efficiency at 145 K. Cross-section transmission electron microscopy and X-ray diffraction study revealed that the structural damage created by H- ions at the high fluence level of 2.4 x 10(15) ions/cm(2), caused the degradation in PL efficiency. (C) 2014 Elsevier B.V. All rights reserved.

A chemical conversion of zinc oxide to zinc sulfide is adapted to create ZnS shell over single crystalline ZnO nanowire. Appearance of an additional peak in x-ray diffraction corresponds to ZnS and strong S 2p(3/2) and S 2p(1/2) peaks in x-ray photoelectron spectroscopy due to Zn-S bonding indicates high quality ZnS shell growth. Reduction in visible light transmittance (approx 15%) is observed in ZnO-ZnS core-shell nanowires which renders higher light absorption. Suppression of defect emission in core-shell nanowires indicates a reduction in surface defects and chemically adsorbed oxygen species. The core-shell geometry also results in an order of increment in charge carrier density (5.3 x 10(18) cm(-3) to 2.8 x 10(19) cm(-3)), i.e. results in an improvement of electrical conductivity and photoelectrochemical performance. Electrochemical solar to hydrogen conversion efficiency is increased to more than double (from 0.15% to 0.38%) due to an improvement in photo-charge carrier separation and collection properties. In comparison to pristine ZnO, photocurrent for ZnO-ZnS core-shell remains same without noticeable fluctuation for few hours, which indicates the ZnS functionalization adds stability to unstable ZnO photoanode. Higher conduction band position of ZnS enhances open circuit photovoltage and reduces photo carrier recombination rate leads to enhancement in photo carrier life time. (C) 2014 Published by Elsevier Ltd.

Core-shell type manganese-doped zinc sulphide nanoparticles ZnS:Mn/ZnS, showing strong absorption of ultraviolet light in the 280-450 nm range and emitting orange-yellow light close to 600 nm, were synthesised for eventual deployment as wavelength down-shifters for solar cells. While most syntheses described in literature employed long reaction times and high reaction/annealing temperatures in excess of 100 degrees C, this work presents a facile low-temperature wet chemical route. Key synthesis parameters including zinc to sulphur ratio, manganese doping percentage, reaction sequence and ultrasonication time - were optimised systematically to achieve optimum orange emission intensity. Nanoparticles with average size similar to 2.3 nm and showing bright orange emission under UV excitation were ultimately achieved. Various characterisation techniques, namely HRTEM, XRD, ICP, ESR, UV-visible absorption spectrometry and fluorescence spectroscopy, were used to probe the nature of the sample. (C) 2013 Elsevier B.V. All rights reserved.

We report on the preparation and characterization of Ag/LiCoO2 nanofibers (NFs) via the sol-gel electrospinning (ES) technique. Ag nanoparticles (NPs) were produced in an aqueous polyvinyl pyrrolidone (PVP) solution by using AgNO3 precursor. A viscous lithium acetate/cobalt acetate/polyvinylalcohol/water (LiAc/(CoAc)(2)/PVA/water) solution was prepared separately. A Ag NPs/PVP/water solution was prepared and added to this viscous solution and magnetically stirred to obtain the final homogeneous electrospinning solution. After establishing the proper electrospinning conditions, as-spun precursor Ag/LiAc/Co(Ac)(2)/PVA/PVP NFs were formed and calcined in air at a temperature of 600 degrees C for 3 h to form well-crystallized porous Ag/LiCoO2 NFs. Various analytical characterization techniques such as UV-vis, SEM, TEM, TGA, XRD, and XPS were performed to analyze Ag NPs, as-spun and calcined NFs. It was established that Ag NPs in the precursor Ag/LiAc/Co(Ac)(2)/PVA/PVP NFs are highly self-aligned as a result of the behavior of Ag in the electric field of the electrospinning setup and the interaction of Ag ions with Li and Co ions in the NE Ag/LiCoO2 NFs exhibit a nanoporous structure compared with undoped LiCoO2 NFs because the atomic radius of Ag is larger than the radius of Co and Li ion; thus, no substitution between Ag and Li or Ag and Co atoms occurs, and Ag NPs are located at the interlayer of LiCoO2 while some are left in the fiber. Nonwovens Cooperative Research Center, NCRC at North Carolina State University Milli Eğitim Bakanlığı - Turkey

Polymer based composites containing metal nanoparticles are shown to provide new substrates for SERS detection and simultaneously enable the development of new tools for molecular sensing. A very important aspect on the use of hybrid materials relates to the observation of synergistic effects that result from the use of distinct components such as a polymer and metal nanoparticles. We report here the preparation of new SERS substrates made from blends of colloidal Au (nanospheres and nanorods) and PtBA (poly(t-butylacrylate)). The observed SERS enhancement depends on the characteristics of the obtained hybrid material. When compared to the starting Au colloids, the Au/PtBA nanocomposites led to SERS spectra with more intense bands, using 2,2'-dithiodipyridine as molecular probe. The origin of the stronger Raman signal in this case, is possibly due to a combination of events related to the nanocomposite characteristics, including the formation of Au assemblies at the polymer surface due to particle clustering, and the absorption increase in a spectral region closer to the laser excitation wavelength. The strategy described here is a low-cost process with potential for the up-scale fabrication of SERS substrates, namely by using other types of nanocomposites. (C) 2013 Elsevier B.V. All rights reserved.

Cd1-xCoxS (0

In this manuscript we present a radiative transfer model for submerged vegetation called SAILHFlood. It simulates reflectance for a partial submerged canopy from vegetation variables, water level, measurement geometry and soil reflectance. It is a version of the proven SAILH model in which, two vegetation layers are included instead of one: the emerged vegetation layer and the submerged vegetation layer, for which the water attenuation is considered. The model validation was performed with a experiment in laboratory conditions varying leaf area index, water level and illumination and observation angles. A least square linear fit of simulated data used to reproduce measured data shows a satisfactory root mean square error (RMSE) of 0.0355, and a spectral angle of 0.2591 radians. The model could be applied to the diversity of vegetation found in flooded situations, both to understand spectral behavior of these environments under different scenarios and to estimate vegetation variables from model inversion. Fil: Beget, M. E.. Instituto Nacional de Tecnología Agropecuaria; Argentina Fil: Bettachini, Víctor. Instituto Nacional de Tecnología Agropecuaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Di Bella, Carlos Marcelo. Instituto Nacional de Tecnología Agropecuaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Baret, F.. Institut National de la Recherche Agronomique; Francia

ZnO nanoparticle samples, which are synthesized by a sol-gel route and collected after various stages of a washing procedure, are systematically investigated using a variety of experimental techniques. The study shows that while the surface charge polarity is positive for the as-grown (unwashed) particles, the surface turns negatively charged when the particles are sufficiently washed. This dissimilar surface charge polarity has been found to result in markedly different luminescence characteristics for the two cases (washed and unwashed). Our study of the luminescence properties under different surrounding conditions furthermore reveals that the major source for the GL emission for these nanoparticles is the hydroxyl groups, which are physisorbed on the surface. (C) 2013 Elsevier B. V. All rights reserved.

We present a thorough and critical study of the electronic properties of the mononitrides of the group IV-V-VI metals (TiN, ZrN, HfN, NbN, TaN, MoN, and WN) grown by Pulsed Laser Deposition (PLD). The microstructure and density of the films have been studied by X-Ray Diffraction (XRD) and Reflectivity (XRR), while their optical properties were investigated by spectral reflectivity at vertical incidence and in-situ reflection electron energy loss spectroscopy (R-EELS). We report the R-EELS spectra for all the binary TMN and we identify their features(metal-d plasmon and N-p + metal-d loss) based on previous ab-initio band structure calculations. The spectral positions of p + d loss peak are rationally grouped according to the electron configuration (i.e. of the respective quantum numbers) of the constituent metal. The assigned and reported R-EELS spectra can be used as a reference database for the colloquial in-situ surface analysis performed in most laboratories. (c) 2012 Elsevier B.V. All rights reserved. Thin Solid Films

Tungsten, silver and tungsten/silver co-doped titania nanopowders were synthesised via an aqueous sol-gel method. The size distribution and zeta potential of the starting sols were determined via photon correlation spectroscopy (PCS). The dried gels were thermally treated at two different temperatures, and the occurrence of amorphous phase was assessed using the combined Rietveld-RIR X-ray powder diffraction method. A systematic study of the optical properties of the powders was made with diffuse reflectance spectroscopy (DRS), and the energy band gaps were calculated using the differential reflectance method; while their morphology was investigated using electron microscopy analysis (TEM). The photocatalytic activity of the samples was assessed in liquid-solid phase, under UVA-light and visible-light irradiation, monitoring the degradation of an organic dye. The influence of the phase composition, optical properties, dimensions, and specific surface area of the powders on the photocatalytic activity was thoroughly discussed. (C) 2012 Elsevier B.V. All rights reserved.

New highly fluorescent calix[4]arene-containing phenylene-alt-ethynylene-3,6- and 2,7-carbazolylene polymers (CALIX-PPE-CBZs) have been synthesized for the first time and their photophysical properties evaluated. Both polymers were obtained in good isolated yields (70–84%), having Mw ranging from 7660–26,700 g mol−1. It was found that the diethynyl substitution (3,6- or 2,7-) pattern on the carbazole monomers markedly influences the degree of polymerization. The amorphous yellow polymers are freely soluble in several nonprotic organic solvents and have excellent film forming abilities. TG/DSC analysis evidences similar thermal behaviors for both polymers despite their quite different molecular weight distributions and main-chain connectivities (Tg in the range 83–95 °C and decomposition onsets around 270 °C). The different conjugation lengths attained by the two polymers dictates much of their photophysical properties. Thus, whereas the fully conjugated CALIX-PPE-2,7-CBZ has its emission maximum at 430 nm (Eg = 2.84 eV; ΦF = 0.62, CHCl3), the 3,6-linked counterpart (CALIX-PPE-3,6-CBZ) fluoresces at 403 nm with a significant lower quantum yield (Eg = 3.06 eV; ΦF = 0.31, CHCl3). The optical properties of both polymers are predominantly governed by the intrachain electronic properties of the conjugated backbones owing to the presence of calix[4]arenes along the polymer chain which disfavor significant interchain interactions, either in fluid- or solid-state.

Deposition of copper indium selenide (Cu1-xInxSe2 (0